Electrical connecting device.



. E. A. COLBY.

ELECTRICAL GONNECTING DEVICE.

APPLICATION FILED DEO.14,1905.

Patented Mar. 30, 1909.y

2 SHEETS-SHBET 1.

ATTOHN EY E. A. CCLBY.

ELECTRICAL CONNECTING DEVICE.

APPLICATION FILED DB0.14,1905.

@l @44. Patented Mar. 30, 1909.

2 SHEETS-SHEET 2.

l r "entran ls'rafrns EDWARD A. COLBY, OF NEWARK,NEW JERSEY.

ELECTRICAL CONN ECTING- DEVICE Specification of Letters Patent.

Patented March 30, 1909.

. Application filed December 14, 1905. Serial No. 291,681.

Tocll whom it may concern.'

Be it known that l, EDWARD A. COLBY, a citizen of the United States, residing at Newark, in the county ol' Essex and State ole New Jersey, have invented certain new and useful Improvement in Electrical Connecting Devices, of which the following is a speciiication.

Much diiiiculty has been found in sealing electric conductors in glass walls, especially where currents of strength exceeding iive or six amperes are to be conveyed. The unequal expansion and contraction'of the metal and the glass cause cracks at the joint thus destroying the vacuum if the glass wall be and in any event forming an imperfect union.

Even when the metal, like platinum, has

substantially the saine rate of expansion per unit of bulk as glass, the unequal radiation of heat from the two bodies whenv the cross sectional area of the conductor is made large enough to carry currents of greater strengths than these above mentioned, results as before in a quicker contraction of the metal, and a like impairment of the joint. I have discovered that this diiiiculty can be coinpletely obviated by constructing the connecting device for the circuit terminals in such a way as that when sealed in the glass all, or practically all, the current is diverted from the seal. Hence at the joint, even if currents very much greater in strength than six amperes are conveyed the difference in temperature between conductor and walls is not suHicient to produce any injurious eii'ect upon the joint.

Inasmuch as there is practically no current passing directly at the joint, the cross sectional area of the metal may there be largely reduced and its surface extended so that the irregularity of radiation may be so far eliminated as to remove any injurious eilects due thereto.

My inventionA consists in the connecting device and the combination Jtherewith of circuit terminals set forth in the claims.

In the accompanying drawings-Figure 1 is a vertical section on the line x x of Fig. 2, of a glass vessel for the treatment oi metals in a vacuum showing my connecting device applied thereto. Fig. 2 is a section of the same on the line y y of Fig. 1 the rods 9, 9, and wire 2 being removed. Fig. 3 is an enlarged section showing the mode of sealing my connecting .device in the wall of the vessel. Fig. 4 is a vertical section of an electrolytic cell, showing my device applied to the glass cups receiving mercury in which the exterior circuit terminals are immersed. Fig. 5 is a section showing my connecting device applied to a glass cup, as before, with the exterior circuit terminal mechanically connected. Fig. 6 shows separately, in section, the platinum thimble constructed as represented in Figs. 4 and 5.

Similar numbers of reference indicate like parts.

Referring iii-st to Figs. 1 to 3 inclusive. 1 is a glass vessel designed to receive metals to be heated in a vacuum by means of the electrically heated wire 2. Said vessel is closed at its lower end by a stopper 3 ground to a tight iit, and is provided with a tube 4,

having a stop cock 5, through which tube air may be exhausted from the vessel by any suitable means. In the wall of said vessel I form an opening and while the glass around said opening is kept in a plastic state by the blow pipe or any other suitable means, I insert therein the cylindrical end portion 6 of a thimble 7 `which is preferably of platinum. The plastic glass is molded around the` exterior of tliethimble so as to form a tight seal. The thinible 7 is preferably produced by spinning a disk of platinum in to substantially the shape shown; that. is to say, with its wall made 'thinner at the open end than elsewhere. By reason oi' this reduction 'in thickness of the `metal at the joint differences in rate of radiationv of metal and 'glass are rendered inconsiderable' in eiiect, and'any impairment of` the joint due to such d1ii`erences is prevented.

The thimble 7 being attached to the wall, in the manner described, I- connect the circuit terminals of both the external current conveying conductors 8 and the internal current conveying conductors 9 to said thimble, so that the current proceeding, for example, from the external conductor 8 to the internal conductor 9 will pass through a portion of the wall `of said thimble distant from the sealed joint; or, in other words, so that said current becomes diverted from the portion of the wall of said thimble at said joint. To this end, I make the diameter of the cylinder at its end cylindrical portion 6 .(whlch cylindrical portion forms part of the joint) greater than at .its body portion. The part of the internal current conveying conductor 9' which is directly connected to the thimble is s t 'mble the separated parts are pressed to-- here a cylindrical rod,l of suitablediameter to fit Within the thimble. The' end ofthe rod is lit, so that when said end is inserted in the the tube 10 are by the insertion of the thim' ble slightly forced apart so that by their spring action they grasp said thimble. e By this construction, current, for example, from tube 10 passes through the wall of thimble 7 to rod 9 above the plane represented by a, b, Fig. 3, which bounds the area of contact between rod 9 and the inner surface of thimble 7. to the joint, which is wholly outside of this plane, the contact area of thimble and conductors may be made large enough to conduct whatever current the conductors themselves are designed to convey. And, furthermore, because of the thinning of the metal at the joint, and the clearance thereatl` between the rod 9 and the thimble, and also because of the increased radiating area of the cylindrical end 6, the variation in dimension of said 'end Will become negligibly small arid not sufficient to impair the integrity 'of the seal.

In the vessel shown in Figs. 1 to 3, there are, of course, two thimbles receiving respectively the plus and minus conductors, andthe two rods 9, which rods are connected byclamping screws 11, to the ends of the heating wire 2.

In Fig. 4, 12 is a cell containing an electrolyte, in which are immersed electrodes 13. The thmble 7, shown se' arately in- Fig. 6, is sealed in the manner a ready described in the end of a glass cup 14 which contains a body of mercury 15 which fills the interior Hence, as no current gets l of-thethimble and partly fills the cup. The external circuit conductor 7 is immersed in the mercury. The thimble is provided with In this case the proportion of current passing from the mercury to thimble, or vice versa, at the joint will be inconsiderably small as compared with the quantity diverted elsewhere.

InFig. 5 the mercury is omitted and the external conductor terminates in a rod 1 7 split at its end, similar to rod 9, and in like manner itting in the thimble.l The condi- -tions aifecting the sealed joint are, therefore, here substantially the same as in Figs. 1, 2 and 3.

' I claim:

.1. A wall of non-conducting material, a tubular support of conducting material, having its end portion of thinner material than its body portion and having said end portion sealed in an opening in said Wall, and separate circuit terminals respectively' connected to the interior and exterior of said body ortion of said su port. y' 2. il) wall Iof non-conducting material, a tubular support having an end portion of larger diameter and of thinner material than its body portion, and having said endl portion sealed in an opening in said wall, and separate circuit terminals respectively connected to the interior and'exterior of said body ortion of said su port. i

3. 111i combination with a wallof non-conducting material, a thimble of metal formed sealed in an o ening in said wall, the metal of said thimb e being of reduced thickness at its open end.

In testimony whereof, I have aflxed my signature in presence of two witnesses.

EDWARD A. COLBY.

Witnesses:

WM. H. SIEGMAN, PARK BENJAMIN, Jr.

with a closed end and having its open end 45o a threaded extension 16 which entersv a simil larly threaded opening in the electrode 13. 

